span.cm-formatting {
    transition: opacity .3s;
}

%hidden-token {
    width: 0px;
    height: 1px;
    opacity: 0;
    overflow: hidden;
    display: inline-block;
}

/* adding some CodeMirror-not-implemented styles' default style */
span.cm-inline-code,
span.cm-math {
    color: #900;
}


div.HyperMD-hover > .HyperMD-hover-content {
    background-color: #fff;
    padding: .5em;
    p {
        margin: .2em 0;
    }
}

.HyperMD-goback {
    width: 1px;
}
div.HyperMD-goback-button {
    background-color: #ddd;
    color: #333;
    text-align: center;
    cursor: pointer;
}

span.hmd-link-icon:after {
    content: "»"
}

span.hmd-fold-math {
    display: inline-block;
    vertical-align: middle;
}

span.cm-formatting-hidden{
     &.cm-formatting-em
    ,&.cm-formatting-strong
    ,&.cm-formatting-strikethrough
    ,&.cm-formatting-quote
    ,&.cm-formatting-code
    ,&.cm-formatting-header
    ,&.cm-formatting-link
    ,&.cm-formatting-escape-char
    ,&.cm-formatting-hmd-stdheader
//  ,&.cm-formatting-footref
//  ,&.cm-formatting-code-block
    {
        @extend %hidden-token;
    }
}